Method for energy management in a hybrid motor vehicle

ABSTRACT

A method is for energy management in a hybrid motor vehicle that includes a power plant coupled with wheels of the vehicle via a transmission according to at least two modes, one of which is currently in use. The method includes determining a quantity of energy representing energy consumption of the power plant and selecting one of the transmission modes according to the quantity of energy. The selecting includes determining a parameter representing an imminent change in torque demand at the wheels, determining a correction factor of the quantity of energy according to the transmission mode currently in use and according to the parameter which represents an imminent change in torque demand, determining a corrected quantity of energy equal to the sum of the quantity of energy plus the correction factor, and selecting the transmission mode in order to minimize the corrected quantity of energy.

TECHNICAL FIELD TO WHICH THE INVENTION RELATES

The present invention relates to a method for energy management in ahybrid motor vehicle comprising a power plant that includes a heatengine and an electric motor suitable for being coupled with wheels ofthe vehicle via a transmission device according to at least twotransmission modes, one of which is currently in use, wherein

a) a quantity of energy is determined which represents the energyconsumption of the power plant, and

b) one of said transmission modes is selected according to this quantityof energy.

TECHNOLOGICAL BACKGROUND

In a hybrid motor vehicle, the power plant is equipped with a heatengine and at least one electric motor, so that several distincttransmission modes can be implemented by a transmission device of thispower plant, in order to couple one or more of these engines/motors withthe driving wheels of the vehicle.

First of all, it is possible to choose to couple only one of these twoengines/motors, or both engines/motors, with the driving wheels of thevehicle, and in fact, for each one of these engines/motors, with a gearratio that is specific to it.

In a hybrid transmission mode, for example, the heat engine as well asthe electric motor are coupled with the driving wheels of the vehicle.In such a hybrid transmission mode, the heat engine and the electricmotor can therefore both contribute to propelling the vehicle, inparticular when high torque must be exerted at the wheels of thevehicle. The heat engine can also, in such a hybrid transmission mode,provide this propulsion alone, while the electric motor remains coupledwith the driving wheels in order to recharge the electric batteryintended to power it.

In contrast, in a transmission mode corresponding to all electricfunctioning, only the electric motor is coupled with the driving wheelsof the vehicle. This all electric transmission mode is particularlyadvantageous in braking phase. In effect, in this case, the kineticenergy of the vehicle can be recovered at least partially in electricalform by means of the electric motor, while the heat engine is uncoupledfrom the wheels of the vehicle and consumes no energy.

On the other hand, when the heat engine and the electric motor are bothcoupled with the driving wheels of the vehicle, the torque to produce inorder to satisfy the torque demand from the driver can be shared, invariable proportions, between these two engines/motors.

Among the different transmission modes that can therefore be used, thetransmission mode to implement is generally selected according to thefunctioning conditions of the vehicle, so as advantageously to minimizethe energy consumption of this vehicle.

But such a selection of the transmission mode, based only on minimizingenergy consumption, can bring about particularly frequent changes oftransmission mode, which is annoying for the users of the vehicle and isnot accompanied by any substantial reduction of the energy consumptionof the vehicle.

In order to resolve this problem, a method is known in particular fromdocument FR3014062 for energy management in a hybrid motor vehicle, inwhich the transmission mode to implement is chosen so as to minimize amixed quantity of energy, which is the sum of a quantity of energyrepresenting the energy consumption of the vehicle plus an annoyancevalue taking into account the annoyance of a change of transmission modefor the users of the vehicle, this method making it possible to limitthe frequency of such changes of transmission mode.

But, when such a management method is used, inappropriate changes oftransmission mode can persist, in particular rapid sequences of changesof transmission mode, during which the vehicle changes transmission modefor a very brief period, which is not accompanied by any substantialenergy saving.

OBJECT OF THE INVENTION

In order to remedy the abovementioned disadvantage of the prior art, thepresent invention proposes a new method for energy management in ahybrid motor vehicle, making it possible efficiently to limit changes oftransmission mode close together in time.

More precisely, the invention proposes a method for energy management ina hybrid motor vehicle as defined in introduction, wherein, at step b),

b1) a parameter is determined which represents an imminent change intorque demand at the wheels,

b2) a correction factor of said quantity of energy is determinedaccording to the transmission mode currently in use and according tosaid parameter which represents an imminent change in torque demand,

b3) a corrected quantity of energy is determined which is equal to thesum of said quantity of energy plus said correction factor,

b4) the transmission mode is selected in order to minimize saidcorrected quantity of energy.

The applicant has effectively found that sequences of rapid changes oftransmission mode take place in particular during changes in torquedemand, generally related to changes of speed of this vehicle.

The method according to the invention therefore authorizes imminentchanges in torque demand of the vehicle to be taken into account inorder to limit the occurrence of these rapid sequences of changes oftransmission mode.

In particular, thanks to the invention, imminent changes in torquedemand (in particular, imminent changes in the speed of the vehicle) aretaken into account in the process for selecting the transmission mode touse, in order to avoid a change of transmission mode which would beunnecessary, because immediately followed by another change oftransmission mode, due for example to the effective change of speed ofthe vehicle.

For example, thanks to the invention, when a motor vehicle approaches azone where it must slow down, for example an intersection, and when thetransmission mode currently in use is an all electric transmission mode,the method according to the invention makes it possible to avoidswitching to a hybrid transmission mode, since the all electrictransmission mode already currently in use is more advantageous in termsof energy during the braking phase than a hybrid transmission mode.

Switching to the hybrid transmission mode just before braking wouldtherefore bring about a first change of transmission mode, which mayentail starting the heat engine when the latter is switched off in allelectric transmission mode, followed almost immediately by a secondchange of transmission mode in order to switch to an all electrictransmission mode at the start of braking.

In a comparable manner, thanks to the invention, when a motor vehicle isabout to accelerate, for example, in order to pass another vehicle, andwhen the transmission mode currently in use is a hybrid transmissionmode, the method according to the invention makes it possible to avoid aswitch to an all electric transmission mode, since the hybridtransmission mode already in use is more advantageous in terms of energyduring the acceleration phase than the all electric transmission mode.

Switching to the all electric transmission mode just before acceleratingwould therefore bring about a first change of transmission mode,followed almost immediately by a second change of transmission mode,with the heat engine restarted in order to switch to a hybridtransmission mode at the start of accelerating.

The parameter which represents an imminent change in torque demand istherefore for example a parameter which represents an imminent change ofspeed of the vehicle.

However, it is noted that the change in torque demand does notnecessarily result from a change of speed. Such a change in torquedemand may also result for example from a change of slope of the roadtraveled by the vehicle at constant speed.

According to the invention, the selection of the transmission mode usedis furthermore based on minimizing the energy consumption, which makesit possible to obtain an optimum compromise between reduced energyconsumption and functioning conditions that are comfortable for theusers of the vehicle.

On the other hand, this method may be implemented in a vehicle by purelysoftware means, based only on data or signals already available in amotor vehicle, in particular when it is equipped with a globalpositioning system (GPS). The implementation of this method thenadvantageously requires no specific additional part or sensor.

Preferably, during the method for energy management according to theinvention, at step a), an initial value of said quantity of energy isdetermined for each transmission mode, this quantity representing theenergy consumption of the power plant; at step b2), a value of saidcorrection factor associated with this transmission mode is determinedfor each transmission mode; at step b3), a final value of said correctedquantity of energy associated with this same transmission mode isdetermined for each transmission mode and at step b4), the transmissionmode is selected which has the lowest final value of the correctedquantity of energy associated with this transmission mode.

It is also possible to envisage that each transmission mode isassociated with a gear ratio and/or with a division of torque betweenthe heat engine and the electric motor.

Other non-limitative and advantageous features of a method for energymanagement in accordance with the invention are as follows:

-   -   said transmission modes comprising at least one hybrid        transmission mode wherein the heat engine and the electric motor        are both coupled with the wheels of the vehicle, and an all        electric transmission mode wherein the electric motor alone is        coupled with the wheels of the vehicle when the transmission        mode currently in use is the all electric transmission mode and        when said parameter determined at step b1) represents an        imminent decrease in torque demand, then, at step b2), said        correction factor is determined so as to have a higher value for        the hybrid transmission mode than for the all electric        transmission mode;    -   when the transmission mode currently in use is the hybrid        transmission mode and when said parameter determined at step b1)        represents an imminent increase in torque demand, then, at step        b2), said correction factor is determined so as to have a higher        value for the all electric transmission mode than for the hybrid        transmission mode;    -   said correction factor is proportional to said quantity of        energy;    -   the vehicle furthermore comprising a global positioning system        suitable for supplying information on the position of the        vehicle and digitized cartographic data, at step b1), said        parameter which represents an imminent change in torque demand        is determined according to said information on the position of        the vehicle and said digitized cartographic data;    -   at step b1), said parameter which represents an imminent change        in torque demand is furthermore determined according to at least        one signal which represents the functioning conditions of the        vehicle;    -   said signal which represents the functioning conditions of the        vehicle comprises at least one of the following signals: a        signal which represents the speed of the vehicle, a signal which        represents the state of the turn signal lights of the vehicle, a        signal which represents the activated or deactivated state of a        cruise control of the vehicle;    -   said quantity of energy is determined by adding the energy        consumption of the heat engine to the energy consumption of the        electric motor, multiplied by an equivalence factor which        represents the relative cost of electrical energy compared with        heat energy for said vehicle; and    -   said quantity of energy is furthermore determined according to        the frequency of rotation of the wheels of the vehicle and/or        with a total torque demanded at the wheels.

DETAILED DESCRIPTION OF AN EMBODIMENT EXAMPLE

The description that will follow with reference to the attacheddrawings, given as non-limitative examples, will bring trueunderstanding of what comprises the invention and how it can beembodied.

On the attached drawings:

FIG. 1 diagrammatically shows steps of a method for energy management ina hybrid vehicle according to the invention,

FIG. 2 is a diagrammatic view of a first road configuration in which amotor vehicle is likely to decelerate,

FIG. 3 is a diagrammatic view of a second road configuration in which amotor vehicle is likely to decelerate,

FIG. 4 is a diagrammatic view of a third road configuration in which amotor vehicle is likely to decelerate, and

FIG. 5 is a diagrammatic view of a fourth road configuration in which amotor vehicle is likely to accelerate.

An example of a method for energy management in a hybrid motor vehicle 1(FIG. 2) according to the invention is explained below.

This vehicle 1 comprises a power plant including a heat engine and anelectric motor suitable for being coupled with driving wheels of thevehicle 1 via a transmission device, according to at least twotransmission modes, one of which is currently in use.

These transmission modes here comprise:

-   -   at least one hybrid transmission mode, wherein the heat engine        and the electric motor are both coupled with the driving wheels        of the vehicle 1, and    -   at least one all electric transmission mode, wherein the        electric motor alone is coupled with the driving wheels of the        vehicle 1.

Each transmission mode corresponds here to a division of torque betweenthe heat engine and the electric motor, and to a traction kinematicsmode.

The electric motor and the heat engine can both contribute, in variableproportions, to the total torque produced by the power plant in order tosatisfy a torque demand on the part of the driver.

Each division of torque between the heat engine and the electric motoris associated here with a value of a first control variable u1, forexample a scalar variable which represents said division of torque.

On the other hand, each traction kinematics mode here designates:

-   -   a choice of coupling one or both engines/motors with the driving        wheels of the vehicle 1 via the transmission device, and    -   for each engine/motor to be coupled with the driving wheels of        the vehicle 1, a value of the gear ratio between this        engine/motor and the driving wheels of the vehicle 1.

As an example, the traction kinematics mode can correspond to asituation in which the electric motor and the heat engine are bothcoupled to the driving wheels of the vehicle 1, respectively with a gearratio equal to 5 and 4.

Each traction kinematics mode is associated here with a value of asecond control variable u2, for example a vectorial variable whichrepresents said traction kinematics mode.

Each transmission mode is therefore associated here with a value of thisfirst control variable u1, and with a value of this second controlvariable u2.

The values of these first u1 and second u2 control variables can be usedhere directly by the power plant, or, here, by an electronic controlunit of the power plant, to control the functioning of the electricmotor, of the heat engine and of the transmission device of the latter.

During such a method for energy management according to the invention,

a) a quantity of energy H which represents the energy consumption of thepower plant is determined, and

b) one of said transmission modes is selected according to this quantityof energy H.

In a noticeable manner, according to the invention, at step b),

b1) a parameter CHG is determined which represents an imminent change intorque demand at the wheels of the vehicle 1 (block 10 of FIG. 1),

b2) a correction factor COR of said quantity of energy H is determined,according to the transmission mode currently in use and according tosaid parameter CHG which represents an imminent change in torque demand(block 11 of FIG. 1),

b3) a corrected quantity of energy HCOR is determined which is equal tothe sum of said quantity of energy H plus said correction factor COR(block 12 of FIG. 1), and

b4) the transmission mode is selected in order to minimize saidcorrected quantity of energy HCOR (block 13 of FIG. 1).

During step a), the quantity of energy H which represents the energyconsumption of the power plant is determined, in accordance with theformula F1 below, by adding an energy consumption Conso_th of the heatengine and an energy consumption Conso_batt of an electric batterypowering the electric motor, the energy consumption Conso_batt of theelectric battery being weighted by multiplying it by an equivalencefactor S:

H=Conso_th(Cth,Wth)+S·Conso_batt(Celec,Welec,SOE)  (F1)

The energy consumption Conso_th of the heat engine is equal to theproduct of the mass flow of fuel consumed Mcarb, multiplied by the lowercalorific value PCI of the fuel:

Conso_th(Cth,Wth)=Mcarb(Cth,Wth)·PCI  (F2)

The lower calorific value PCI of the fuel makes it possible to convert amass flow of fuel, expressed in grams per second, to a consumed power,expressed in Watt.

The mass flow of fuel Mcarb is determined on the basis of fuel flowcartography, according to a functioning point of the heat engine definedby a torque value Cth produced by the heat engine, and by an engine rpmWth of this engine, which corresponds to the frequency or speed ofrotation of the engine.

The energy consumption Conso_batt of the electric battery powering theelectric motor is determined on the basis of cartography of the powerabsorbed or supplied by the electric motor, according to:

-   -   a functioning point of the heat engine defined by a torque value        Celec produced by the electric motor and by a motor power Welec        of this motor, and    -   a value which represents a state of energy SOE of this battery.

This state of energy SOE corresponds for example to the relation of theenergy available in the battery divided by the rated energy for thisbattery, that is to say, by the maximum quantity of energy this batterycan contain.

The energy consumption Conso_batt of this electric battery can havepositive or negative values. Such negative values can be obtained forexample during a regenerative braking phase during which a portion ofthe kinetic energy of the vehicle 1 is recovered in electrical form viathe electric motor.

In an optional manner, the energy consumption Conso_batt of the electricbattery powering the electric motor is also determined by taking intoaccount the energy consumption of accessories of the vehicle 1, forexample the energy consumption of illuminating devices of the vehicle.

The equivalence factor S weights the consumption of energy of electricalorigin relative to the consumption of energy of thermal origin accordingto their relative cost. In other words, the equivalence factor S fixesthe cost of energy of electrical origin relative to the cost of acorresponding mass of fuel. A low value of this equivalence factor Sfavors a consumption of the energy stored in electrical form by saidelectric battery. A high value of this equivalence factor S on thecontrary favors a consumption of energy of thermal origin, which resultsin preserving the energy stored in electrical form by said electricbattery, and even in recharging this battery.

The value of the equivalence factor S is determined here according tothe state of energy SOE of the electric battery.

As a variant, the quantity of energy H which represents the energyconsumption of the power plant is determined by directly adding anenergy consumption of the heat engine to an energy consumption of anelectric battery powering the electric motor, without weighting.

In practice here, at step a), a value of the quantity of energy H whichrepresents the energy consumption of the power plant, is determined, foreach transmission mode, according to the values of the first and secondcontrol variables u1, u2 corresponding to this transmission mode, asexplained below.

This value of the quantity of energy H is furthermore determinedaccording to:

-   -   the frequency of rotation Froue at the driving wheels of the        vehicle 1,    -   the total torque Ctotal to produce at these wheels in order to        satisfy the torque demand on the part of the driver, and    -   the state of energy SOE of said electric battery.

The value of each of these functioning parameters of the vehicle 1 isdetermined by the equipment of the vehicle 1.

In effect, the vehicle 1 here comprises a sensor suitable for measuringthe frequency of rotation Froue at the driving wheels.

The total torque Ctotal to produce at these wheels is determined in turnaccording to the torque demanded by the driver at the accelerator pedalor at the brake pedal. It will be noted that the total torque can havepositive values, but also negative values, for example in braking phase.

Finally, the state of energy SOE of the electric battery powering theelectric motor can be determined on the basis of electrical measurementsconcerning this battery, in accordance with any method known to theperson skilled in the art.

The rpm Wth of the heat engine and the power Welec of the electric motorare determined for example in accordance with the following relations F3and F4:

Wth=Rth(u2)·Froue  (F3)

Welec=Relec(u2)·Froue  (F4)

The value of the gear ratio Rth between the heat engine and the drivingwheels of the vehicle 1, and the value of the gear ratio Relec betweenthe electric motor and these wheels, are each determined on the basis ofthe value of the second control variable u2, since the latter representsa given traction kinematics mode.

The value of the torque Celec produced by the electric motor and that ofthe torque Cth produced by the heat engine are deduced:

-   -   from the following relation F5

Ctotal=Rth(u2)·Cth+Relec(u2)·Celec  (F5)

-   -   and from the division of torque between the heat engine and the        electric motor.

This division of torque is deduced from the value of the first controlvariable u1.

Here, for example, the first control variable u1 is equal to therelation of the torque produced by the heat engine at the driving wheelsof the vehicle, divided by the total torque produced by the power plantat these wheels:

u1=Rth(u2)·Cth/Ctotal  (F6).

The relation F5 therefore effectively makes it possible to determine thevalue of the torque Celec produced by the electric motor and that of thetorque Cth produced by the heat engine according to the values of thefirst and second control variables u1, u2, for a given value of thetorque Ctotal to supply in order to satisfy the torque demand on thepart of the driver of the vehicle 1.

Here, more particularly, during step a), for each transmission mode, aninitial value of said quantity of energy H is determined whichrepresents the energy consumption of the power plant.

At step b1), during which a parameter CHG is determined which representsan imminent change in torque demand, the following steps are performed:

b11) a road configuration is identified which is likely to correspond toan increase or a decrease of the demanded torque, for example due toimminent acceleration or deceleration of the vehicle 1, according toinformation on the position of the vehicle 1 determined by a globalpositioning system, and according to digitized cartographic data,

b12) the situation of the vehicle 1 is determined as a situation ofeffective increase or decrease of the torque demand, for example, asituation of effective imminent acceleration or deceleration, bycombining data which represent the identified road configuration withsignals which represent the functioning of the vehicle 1, in particularsignals which represent an intention on the part of the driver to changedirection and/or speed, and

b13) the parameter CHG is determined which represents an imminent changein torque demand.

The global positioning system used during the sub-step b11) is forexample a navigation system of the vehicle 1.

This navigation system makes it possible, for example, thanks to GPS orGMS (Global System for Mobile Communication) signals it receives, todetermine said information on the position of the vehicle 1, here thegeographic coordinates identifying the vehicle 1.

This navigation system also comprises said digitized cartographic data.These cartographic data describe in particular the network of trafficroutes used by the vehicle 1. These cartographic data describe inparticular the configuration of these traffic routes and indicate acorresponding maximum authorized speed VMA.

The vehicle 1 can therefore be localized on this network of trafficroutes, for example by a process of matching its geographic coordinatesand said digitized geographic data (map matching process). The precisionof this localization of the vehicle 1 on this road network can beimproved by taking into account odometric data of the vehicle 1, that isto say by taking into account the number of meters traveled by thisvehicle from a given position.

The digitized cartographic data used in this navigation system areglobally described as explained below.

Each road segment is described by an arc, to which data describing thisroad segment can be associated, such as:

-   -   the maximum authorized speed VMA on this segment;    -   the number of traffic lanes and the direction of traffic which        corresponds to them;    -   the functional category of the road, which indicates whether it        is a segment of track, for example, or whether it is a segment        of freeway or national highway; these different functional        categories are classified here in ascending order, from the one        corresponding to a track through to the one corresponding to a        freeway; and    -   optionally, the average speed of the vehicles present on this        segment or on this road, these data originating for example from        information on the state of the road traffic received by the        navigation system from a telecommunications network.

Each arc is furthermore described by points, or nodes, situated alongthis arc. The position of each node is known, in particular thecorresponding latitude, longitude and altitude. The nodes of an arctherefore make it possible to describe the shape of the road segmentunder consideration.

Each node can furthermore carry information relating to the propertiesof the corresponding road segment, at the node under consideration, suchas for example:

-   -   the presence of a road sign at this node, for example a sign        signaling a STOP;    -   a bend radius value RC of the road segment at this node; these        data can thus inform of the presence of a tight bend,    -   the presence of a level crossing or a speed bump at this node,    -   the presence of an intersection at this node, the result of        which for the navigation system is the fact that this node        belongs to several arcs having different orientations.

The digitized cartographic data therefore comprise data describing theportion of road which faces the vehicle 1 and making it possible toidentify, for the vehicle 1, a road configuration likely to correspondto an imminent increase or decrease of the demanded torque, generallylinked with imminent deceleration or acceleration, but potentiallylinked with a change of slope of the road traveled by the vehicle 1 atconstant speed.

This road configuration corresponds for example to a change of aproperty of the road traveled by the vehicle 1 or to a change of trafficconditions, such as:

-   -   a change of slope,    -   a change of the number of traffic lanes,    -   a change of direction corresponding to a tight bend or an        intersection,    -   a change of speed limit,    -   an obligation to stop the vehicle 1, indicated for example by a        road sign device, or    -   passing from a zone not too busy with traffic to a zone busy        with traffic, or vice-versa.

FIGS. 2 to 5 diagrammatically show four examples of road configurationsin which the motor vehicle 1 is likely either to decelerate or toaccelerate, and therefore to bring about a change in torque demand atthe wheels.

In a first road configuration shown on FIG. 2, the motor vehicle 1approaches an intersection 20 connecting the segment 21 on which thevehicle 1 is situated with three other road segments 22, 23, 24, ofwhich one 22 is a prohibited direction, and of which the other two 22,23 are authorized and have an orientation different from that of thesegment 21 on which the vehicle 1 is situated.

In a second road configuration shown on FIG. 3, the motor vehicle 1approaches an intersection 30 equipped, for the road segment 31 traveledby the vehicle 1, with a road sign 32 signaling a STOP.

In a third road configuration shown on FIG. 4, the motor vehicle 1approaches an intersection 40 connecting four road segments 41, 42, 43,44, each with two-way traffic, said intersection having no road panelsor signs.

The first, second and third road configurations shown on FIGS. 2 to 4are likely to lead to the vehicle 1 decelerating, and therefore to adecrease in torque demand at the wheels.

In a fourth road configuration shown on FIG. 5, the motor vehicle 1 issituated on a road segment 51 on which the maximum authorized speed is90 kilometers an hour, extended by a segment of freeway 52 on which themaximum authorized speed is 90, 110 or 130 kilometers an hour dependingon the meteorological conditions and the vehicle type.

The fourth road configuration of FIG. 5 is likely to lead to the vehicle1 accelerating, and therefore to an increase in torque demand at thewheels. When one of the road configurations likely to correspond toimminent deceleration of the vehicle 1 is identified, sub-step b11) isfurther accompanied by:

-   -   determining a value of the distance D separating the current        position of the vehicle 1 and the position of the road element        likely to cause said deceleration, and    -   determining the value of a passing speed VP recommended for the        vehicle 1 at said road element.

This road element corresponds for example, in the case shown on FIG. 3,to the sign signaling the STOP, which should be marked at thecorresponding intersection.

The value of this distance D is determined here on the basis of thecurrent position of the vehicle 1 and the position of said road element,each identified on the network of traffic routes described by saidcartographic data.

The value of the recommended passing speed VP corresponds, for some roadconfigurations, to a given predetermined value. For example, it is takenhere to be equal to 20 kilometers an hour for an intersection where thevehicle 1 will be obliged to branch off toward a road segment which isnot a prolongation thereof, as shown in FIG. 2.

For other road configurations, the value of this recommended passingspeed VP is determined on the basis of data describing the portion ofroad facing the vehicle 1, data which are available in the navigationsystem. These data can correspond for example to the maximum authorizedspeed VMA, or to the bend radius RC of the road, at the node identifyingsaid road element likely to engender deceleration.

In particular, when this road element corresponds to a tight bend, thevalue of the recommended passing speed VP here is equal to a maximumspeed Vmax(RC) associated with the bend radius RC of this bend, thisspeed being determined in accordance with the following formula F9:

VP=Vmax(RC)=λ·3,6·√{square root over (g·μ _(max) ·RC)}  (F9)

where:

-   -   the maximum speed Vmax(RC) associated with the bend radius RC of        this bend is expressed in kilometers an hour,    -   the bend radius RC of this bend is expressed in meters,    -   μ_(max) is a coefficient of maximum lateral adherence of the        vehicle,    -   g is acceleration due to gravity, expressed in meters per second        squared,    -   and λ is a coefficient of safety, positive and less than 1,        whose value is predetermined such that this recommended passing        speed VP is less than a limit speed beyond which the vehicle 1        would skid in this bend, so as to conserve a safety margin        between the recommended passing speed VP and this limit speed.

Tables 1 and 2 below gather together examples of road configurationsidentified as likely to correspond to imminent acceleration ordeceleration. The configurations described in these tables are given asexamples; other road configurations encountered by a motor vehicle arelikely to correspond to imminent acceleration or deceleration.

TABLE 1 examples of road configurations likely to correspond to imminentacceleration code of the identified road configuration description ofthe road configuration A1 The vehicle 1 is on an access slip road to afreeway (FIG. 5): for the current segment, the functional category islower than that for a freeway, and VMA ≤ 90 km/h, for the followingsegment, the functional category is that of a freeway and VMA ≥ 90 km/h.A2 The vehicle 1 is on a road with the possibility of passing; for thecurrent segment: 50 km/h ≤ VMA ≤ 90 km/h, the number of traffic lanes inthe direction of travel is more than 2, and over the next 500 meters,there are no nodes corresponding to an intersection. A3 The vehicle 1 ison a freeway; for the current segment, the functional category is thatof a freeway and VMA ≥ 90 km/h.

TABLE 2 examples of road configurations likely to correspond to imminentdeceleration code of the Recommended identified road passing speedconfiguration description of the road configuration VP D1 The vehicle 1approaches a STOP (FIG. 3): 0 the current segment comprises a node whichcorresponds to an intersection, and at which a STOP sign is indicated.D2 The vehicle 1 approaches an intersection obliging it to 20 km/hchange direction (FIG. 2): the current segment comprises a node whichcorresponds to an intersection, the following authorized segments (nothaving a prohibited direction) have an orientation different from thatof the current segment. D3 The vehicle 1 approaches an intersectionoffering at 20 km/h least one possibility of changing direction (FIG.4): the current segment comprises a node which corresponds to anintersection, at least one subsequent authorized segment has anorientation different from that of the current segment. D4 The vehicle 1is on an exit slip road from a freeway, equal to the VMA approaching anexit. associated with this exit slip road D5 The vehicle 1 approaches abend: equal to Vmax the current segment contains a node for which a bend(RC) radius RC < 100 m is indicated. D6 The vehicle 1 approaches atraffic circle: Vmax(RC) the current segment contains a nodecorresponding to an intersection, and this segment corresponds to atraffic circle.

During the following sub-step b12), an evaluation is performed as towhether the situation of the vehicle 1 is a situation of effectiveincreased or reduced torque demand, due for example to an effectiveimminent acceleration or deceleration situation.

For this purpose, data which represent the road configuration identifiedat the preceding sub-step b11) are combined with signals which representthe functioning of the vehicle 1, in particular signals which representan intention on the part of the driver to change direction and/or speed.

Said data which represent the identified road configuration herecomprise for example:

-   -   a code associated with this road configuration, indicated in        tables 1 and 2 for the corresponding examples of road        configurations,    -   a maximum authorized speed VMA in this road configuration, and    -   when the identified road configuration is likely to correspond        to imminent deceleration of the vehicle 1, a value of the limit        distance DLIM and a value of the recommended passing speed VP.

The signals which represent functioning conditions of the vehicle usedfor this purpose comprise here for example:

-   -   a signal which represents the speed V of the vehicle 1,    -   a signal which represents the state of the turn signal lights of        the vehicle, namely: extinguished, hazard warning, right turn        signal light active or left turn signal light active, and    -   a signal which represents the activated or deactivated state of        a cruise control equipping the vehicle 1.

In the road configurations where the vehicle 1 travels on a freeway oron a road with a possibility of passing, which corresponds for exampleto the road configurations A3 and A2 of table 1, the fact that the leftturn signal light is active indicates a probable intention on the partof the driver of the vehicle 1 to pass another vehicle. In this case, ifthe cruise control is inactive, the vehicle 1 is determined as being ina situation of effective imminent acceleration.

In contrast, when the vehicle 1 travels on a freeway, and its left turnsignal light is active, but the cruise control is activated, it isconsidered here that the vehicle will be kept at a substantiallyconstant speed, and it is therefore determined that the vehicle 1 is notin a situation of effective imminent acceleration.

On the other hand, in one of the road configurations where the vehicle 1approaches an intersection offering at least one possibility of changingdirection (FIG. 4), which corresponds for example to the configurationD3 of table 2, the fact that the left or right turn signal light isactive indicates a probable intention on the part of the driver of thevehicle 1 to change direction. In this case, it is determined that thevehicle 1 is in a situation of effective imminent deceleration.

Furthermore, in one of the road configurations likely to correspond toimminent acceleration, when the speed V of the vehicle 1 is close to themaximum authorized speed VMA on the road segment traveled, it isdetermined at step b12) that the vehicle 1 is not in a situation ofeffective imminent acceleration, since it is not authorizedsubstantially to increase its speed V.

In a comparable manner, in one of the road configurations likely tocorrespond to imminent deceleration, when the speed V of the vehicle 1is close to the passing speed VP recommended in this road configuration,it is determined here that the vehicle 1 is not in a situation ofeffective imminent deceleration, since its speed is already sufficientlylow to be suitable for the road configuration encountered.

Tables 3 and 4 below summarize, for the examples of road configurationsdescribed in tables 1 and 2, the conditions to verify in order todetermine that the vehicle 1 is in a situation of effective imminentacceleration or deceleration.

TABLE 3 conditions to verify in order to determine that the vehicle 1 iseffectively in a situation of effective imminent acceleration differencebetween code of the state the maximum authorized identified state of theof the speed VMA on the road turn signal cruise segment traveled and theconfiguration lights control speed V of the vehicle 1 A1 any any VMA −V > 20 km/h A2 left turn signal deactivated any difference in speedlight active A3 left turn signal deactivated VMA − V > 20 km/h lightactive

TABLE 4 conditions to verify in order to determine that the vehicle 1 iseffectively in a situation of effective imminent deceleration code ofthe difference between the speed V of identified road state of the turnsignal state of the the vehicle 1 and the recommended configurationlights cruise control passing speed VP D1 any any any difference inspeed D2 any any V − VP > 20 km/h D3 left or right turn signal any V −VP > 20 km/h light active D4 right turn signal light deactivated V −VP > 20 km/h active D5 any any V − VP > 20 km/h D6 any any V − VP > 20km/h

The conditions described above, concerning the state of the turn signallights, are given here for motor vehicle traffic on the right (such astraffic in France or Germany, for example). The person skilled in theart will be able to adapt them without difficulty to the case of motorvehicle traffic on the left (such as traffic in the United Kingdom orJapan, for example).

At sub-step b13), the parameter CHG is a variable here which is able toadopt three different values:

-   -   a first value, for example 0, indicating probably keeping the        torque demand at the wheels of the vehicle 1 at a substantially        constant value, for example in the case of probably keeping the        speed of the vehicle 1 on a flat road,    -   a second value, for example 1, indicating an imminent increase        in torque demand, due for example to imminent acceleration on a        flat road, and    -   a third value, for example 2, indicating an imminent decrease in        torque demand, due for example to imminent deceleration on a        flat road.

By default, the value 0 is attributed here to the parameter CHG.

When the situation of effective imminent acceleration has beendetermined during the preceding sub-step b12), and in a case where theroad traveled is flat, the value 1 is attributed to the parameter CHG,and in fact:

-   -   as soon as this situation of effective imminent acceleration is        determined,    -   and for a period shorter than a given maximum period.

Here, this given maximum period is less than 20 seconds.

When a period longer than this maximum period has elapsed since thesituation of effective imminent acceleration was determined, the value 0is once more attributed to the parameter CHG.

The period during which the value 1 is attributed to the parameter CHG,further to the determination of the situation of effective imminentacceleration, is limited in order to avoid keeping this value at 1 in acase where the driver of the vehicle finally decides not to accelerate.

When the situation of effective imminent deceleration is determined, andin a case where the road traveled is flat, the value 2 is attributed tothe parameter CHG, and in fact:

-   -   as soon as the distance D which separates the vehicle 1 from the        road element responsible for said deceleration is less than a        limit distance DLIM,    -   and as long as this road element has not been passed.

This limit distance DLIM is determined according to the speed V of thevehicle 1; it is all the greater given that the speed V of the vehicle 1is high.

This arrangement advantageously makes it possible to signal a situationof effective deceleration all the more distant from the deceleratingelement given that the speed V of the vehicle 1 is high.

Here for example, the following limit distance values are adopted:

-   -   DLIM=300 meters where V=100 kilometers an hour, and    -   DLIM=40 meters where V=30 kilometers an hour.

As a variant, the parameter CHG which represents an imminent change ofspeed of the vehicle is furthermore determined, during step b1),according to other data or signals relating to the functioning of themotor vehicle, for example data which represent images of thesurroundings facing the vehicle 1, acquired by a camera equipping thisvehicle and processed by means of suitable software.

The correction factor COR is determined so as to penalize switching ofthe power plant to a transmission mode that will become unfavorable interms of energy after the change of speed of the vehicle.

More precisely, here, the correction factor COR is determined so as topenalize switching of the power plant to a kinematics mode offering achoice of one or both engines/motors which will become unfavorable interms of energy after the change of speed of the vehicle.

Here, when the parameter CHG which represents an imminent change intorque demand indicates that a decrease in the demanded torque isimminent, and when the transmission mode currently in use is one of theall electric transmission modes, the correction factor COR correspondingto each hybrid transmission mode is then determined so as to be higherthan that corresponding to any one of the all electric transmissionmodes.

The correction factor COR in this case is a factor which penalizesswitching to one of the hybrid transmission modes. It favors keeping toone of the all electric transmission modes.

More precisely, in such a case, the correction factor COR here is:

-   -   equal to a fraction of the absolute value of said quantity of        energy H: COR=CAL1·|H| (F7) for each hybrid transmission mode,        and    -   equal to 0 for each all electric transmission mode.

For each hybrid transmission mode of the vehicle, the amplitude of thecorrection factor COR, relative to said quantity of energy H, is givenby a first calibration constant CAL1, positive. Furthermore, thequantity of energy H is taken as an absolute value for determining thiscorrection factor COR, such that the latter remains positive even whenthe quantity of energy H adopts a negative value, for example during aregenerative braking phase.

In a comparable manner, here, when the parameter CHG which represents animminent change in torque demand indicates that an increase of thedemanded torque is imminent and when the transmission mode currently inuse is one of the hybrid transmission modes, the correction factor CORcorresponding to each all electric transmission mode is then determinedso as to be higher than that corresponding to any one of the hybridtransmission modes.

The correction factor COR is then a factor penalizing switching to oneof the all electric transmission modes. It favors keeping the powerplant in one of the hybrid transmission modes.

More precisely, in such a case, the correction factor COR here is:

-   -   equal to a fraction of the absolute value of said quantity of        energy H: COR=CAL2·|H| (F8) for each all electric transmission        mode, and    -   equal to 0 for each hybrid transmission mode.

The second calibration constant CAL2 is there again positive. Here, thefirst CAL1 and the second CAL2 calibration constants have the samevalue. As a variant, the first CAL1 and the second CAL2 calibrationconstants have different values.

On the other hand, here, when the situation in which the vehicle residescorresponds:

-   -   neither to an imminent increase of the demanded torque and to a        hybrid transmission mode currently in use,    -   nor to an imminent decrease of the demanded torque and to an all        electric transmission mode currently in use,

then the correction factor COR is determined such that it is identicalfor all the transmission modes.

More precisely, here, the correction factor COR is taken to be equal to0 for each transmission mode, in such a case.

As a variant, the correction factor is determined according to any othermethod tailored:

-   -   so that the correction factor corresponding to each hybrid        transmission mode is higher than the correction factor        corresponding to any one of the all electric transmission modes        when the parameter which represents an imminent change in torque        demand indicates that a decrease of the demanded torque is        imminent, and when the transmission mode currently in use is an        all electric transmission mode, and    -   so that the correction factor corresponding to each all electric        transmission mode is higher than the correction factor        corresponding to any one of the hybrid transmission modes when        the parameter which represents an imminent change in torque        demand indicates that an increase of the demanded torque is        imminent, and when the transmission mode currently in use is a        hybrid transmission mode.

Here, more particularly, during step b2), a value of said correctionfactor is determined for each transmission mode, this value beingassociated with this transmission mode.

During step b3), the corrected quantity of energy HCOR is determined byadding the quantity of energy H which represents the energy consumptionof the vehicle 1 to said correction factor COR:

HCOR=H+COR  (F9)

Here, more particularly, a final value associated with said correctedquantity of energy HCOR is determined for each transmission mode.

During step b4), the transmission mode is selected in order to minimizesaid corrected quantity of energy HCOR.

For this, the transmission mode having the final value of the correctedquantity of energy HCOR is selected here, this value being associatedwith this weakest transmission mode.

The method for determining the quantity of energy H and the correctionfactor COR described above, combined with selecting a transmission modeby minimizing the corrected quantity of energy HCOR, advantageouslyallows the energy consumption of the vehicle 1 to be minimized, whileavoiding changing transmission mode in a situation where this changewould be followed almost immediately by a return to the initialtransmission mode due to a change in demanded torque, for example due toa change of speed of the vehicle.

In particular, when a decrease of the demanded torque is imminent andthe transmission mode currently in use is one of the all electrictransmission modes, each hybrid transmission mode is advantageouslyunlikely to be selected here, since the correction factor COR associatedwith it is higher in this case than that associated with any one of theall electric transmission modes, and since said selection is made byminimizing said corrected quantity of energy HCOR.

In a comparable manner, when an increase of the demanded torque isimminent and the transmission mode currently in use is one of the hybridtransmission modes, one of the all electric transmission modes isadvantageously unlikely to be selected here, since the correction factorCOR associated with it is higher in this case than that associated withany one of the hybrid transmission modes.

In the example of FIG. 3, two transmission modes are considered:

-   -   an all electric transmission mode ZEV1, and    -   a hybrid transmission mode Hyb1.

In this example, the vehicle 1 approaches an intersection where it mustmark a STOP (FIG. 3). This corresponds to one of the road configurationslikely to correspond to deceleration. This road configuration isassociated with a situation of effective deceleration, and therefore ofdecrease in the torque demanded at the wheels, whatever the values ofsaid signals which represent the functioning conditions of the vehicle1.

The transmission mode currently in use is the mode ZEV1.

In this first situation, the quantity of energy H which represents theenergy consumption of the power plant has the following values:

-   -   for the transmission mode ZEV1:

H(ZEV1)=(1 gram per second).PCI

-   -   and for the transmission mode Hyb1:

H(Hyb1)=(0.9 gram per second).PCI

Furthermore, in this initial situation, the parameter CHG whichrepresents an imminent change in torque demand indicates here animminent decrease of the demanded torque. The value of the firstcalibration constant CAL1 is 20% here, namely CAL1=0.2. In this initialsituation, the correction factor COR and the corrected quantity ofenergy HCOR therefore have the following values:

-   -   for the transmission mode ZEV1:

COR(ZEV1)=0

HCOR(ZEV1)=(1 gram per second).PCI

-   -   and for the transmission mode Hyb1:

COR(Hyb1)=(0.18 gram per second).PCI and

HCOR(Hyb1)=(1.08 gram per second).PCI.

The corrected quantity of energy HCOR therefore has a smaller value forthe transmission mode ZEV1 than for the transmission mode Hyb1.

The selected transmission mode is then the transmission mode ZEV1, andtherefore it is this mode which continues to be used in the vehicle 1.

Subsequently, as the vehicle 1 approaches the intersection, its driverbrakes and the speed of the vehicle 1 decreases. In this secondsituation, said quantity of energy H, the correction factor COR and thecorrected quantity of energy HCOR have the following values:

-   -   for the transmission mode ZEV1:

H(ZEV1)=(−0.3 gram per second).PCI

COR(ZEV1)=0

HCOR(ZEV1)=(−0.3 gram per second).PCI

-   -   and for the transmission mode Hyb1:

H(Hyb1)=(0.1 gram per second).PCI

COR(Hyb1)=(0.02 gram per second).PCI and

HCOR(Hyb1)=(0.12 gram per second).PCI.

The selected transmission mode is then the transmission mode ZEV1, andtherefore it is this mode which still continues to be used in thevehicle 1.

Therefore, thanks to the invention, selection of the hybrid transmissionmode Hyb1 is avoided in the first situation. In effect, if this modewere to be selected, it would only be used for a very short time beforereturning to the all electric transmission mode ZEV1 in the secondsituation. Such rapid changes of transmission mode are perceived asannoying by the driver.

In a variant of this method for energy management according to theinvention, it is furthermore envisaged, at step b2), when the parameterwhich represents an imminent change in torque demand indicates adecrease in the demanded torque linked with imminent deceleration, andwhen the transmission mode currently in use is one of the hybridtransmission modes, that the correction factor is determined such thatit has, for one of the hybrid transmission modes which corresponds to agear ratio of the heat engine lower than the gear ratio of the heatengine currently in use, a value higher than that associated with thetransmission mode currently in use.

For a vehicle traveling at slow speed, the use of a high gear ratio isknown for coupling a heat engine to wheels of this vehicle, such thatthis engine is used on a good functioning point. Whereas the use isknown of a lower gear ratio when the speed of the vehicle is high.

The method for determining the correction factor corresponding to thisvariant advantageously allows a change of transmission mode to beavoided which would result in a reduction of the gear ratio of the heatengine even when the vehicle is about to decelerate. It is advantageousto avoid this change of transmission mode, as it would be followedalmost immediately, due to the reduction in speed of the vehicle, byanother change of transmission mode allowing a return to a high gearratio of the heat engine.

The correction factor COR is determined here so as to penalize switchingof the power plant to a kinematics mode having a gear ratio which willbecome unfavorable after the change in speed of the vehicle.

In an optional manner, it is furthermore envisaged in this variant: whenthe parameter which represents an imminent change in torque demandindicates an increase of the demanded torque linked with imminentacceleration, and when the transmission mode currently in use is one ofthe hybrid transmission modes, that the correction factor is determinedso as to favor the selection of one of the hybrid transmission modeswhich corresponds to a gear ratio of the heat engine higher than thegear ratio of the heat engine currently in use.

This last arrangement advantageously allows a change of transmissionmode to be induced which results in an increase of the gear ratio of theheat engine, that is to say to downshift when the vehicle is about toaccelerate. The driving comfort is therefore further improved since theacceptable ratio is favored with the largest possible reserve ofavailable torque.

1-9. (canceled)
 10. A method for energy management in a hybrid motorvehicle comprising a power plant that includes a heat engine and anelectric motor suitable for being coupled with wheels of the vehicle viaa transmission device according to at least two transmission modes, oneof which is currently in use, the method comprising: a) determining aquantity of energy which represents the energy consumption of the powerplant; and b) selecting one of said transmission modes according to thequantity of energy, wherein the selecting includes: b1) determining aparameter which represents an imminent change in torque demand at thewheels, b2) determining a correction factor of said quantity of energyaccording to the transmission mode currently in use and according tosaid parameter which represents an imminent change in torque demand, b3)determining a corrected quantity of energy which is equal to the sum ofsaid quantity of energy plus said correction factor, and b4) selectingthe transmission mode in order to minimize said corrected quantity ofenergy.
 11. The method for energy management as claimed in claim 10,wherein: at a), an initial value of said quantity of energy isdetermined for each transmission mode, the quantity of energyrepresenting the energy consumption of the power plant; at b2), a valueof said correction factor associated with the transmission mode isdetermined for each transmission mode; at b3), a final value of saidcorrected quantity of energy associated with the same transmission modeis determined for each transmission mode; and at b4), the transmissionmode is selected which has the lowest final value of the correctedquantity of energy associated with the transmission mode.
 12. The methodas claimed in claim 10, wherein each transmission mode is associatedwith a gear ratio and/or with a division of torque between the heatengine and the electric motor.
 13. The method as claimed in claim 10,wherein said transmission modes include at least one hybrid transmissionmode in which the heat engine and the electric motor are both coupledwith the wheels of the vehicle, and an all electric transmission mode inwhich the electric motor alone is coupled with the wheels of thevehicle, and when the transmission mode currently in use is the allelectric transmission mode and when said parameter determined at b1)represents an imminent decrease in torque demand, then, at b2), saidcorrection factor is determined so as to have a higher value for thehybrid transmission mode than for the all electric transmission mode.14. The method as claimed in claim 10, wherein said transmission modesinclude at least one hybrid transmission mode in which the heat engineand the electric motor are both coupled with the wheels of the vehicle,and an all electric transmission mode in which the electric motor aloneis coupled with the wheels of the vehicle, and when the transmissionmode currently in use is the hybrid transmission mode and when saidparameter determined at b1) represents an imminent increase in torquedemand, then, at b2), said correction factor is determined so as to havea higher value for the all electric transmission mode than for thehybrid transmission mode.
 15. The method as claimed in claim 10, whereinsaid correction factor is proportional to said quantity of energy. 16.The method as claimed in claim 10, wherein the vehicle further comprisesa global positioning system suitable for supplying information on aposition of the vehicle and digitized cartographic data, and at b1),said parameter which represents the imminent change in torque demand isdetermined according to said information on the position of the vehicleand said digitized cartographic data.
 17. The method as claimed in claim10, wherein, at b1), said parameter which represents the imminent changein torque demand is determined according to at least one signal whichrepresents functioning conditions of the vehicle.
 18. The method asclaimed in claim 17, wherein said signal which represents thefunctioning conditions of the vehicle comprises at least one of thefollowing signals: a signal which represents a speed of the vehicle, asignal which represents a state of turn signal lights of the vehicle,and a signal which represents an activated or deactivated state of acruise control of the vehicle.